Package-on-package (POP) is becoming an increasingly popular integrated circuit packaging technique because it allows for higher density electronics.
A conventional package-on-package structure may include a bottom package component and a top package component. The bottom package component may include a bottom die attached to a bottom substrate and the top package component may include a top die attached to a top substrate. The bottom package component is coupled to the top package component typically by a set of conductive elements, such as solder balls. In operation, both package components generate heat. However, excessive heat that is generated by the bottom die, especially where the bottom die is a device die, may cause damage to the top die. The heat can also cause thermal stress and warpage in the package-on-package structure leading to cracks in the solder balls. Even with the use of molding compounds in the package-on-package structure, the problem of excess heat and warpage still cannot be entirely eliminated.